Brain Plasticity Modulator p75 Neurotrophin Receptor in Human Urine after Different Acute Brain Injuries-A Prospective Cohort Study

Acute brain injuries (ABIs) pose a substantial global burden, demanding effective prognostic indicators for outcomes. This study explores the potential of urinary p75 neurotrophin receptor (p75NTR) concentration as a prognostic biomarker, particularly in relation to unfavorable outcomes. The study involved 46 ABI patients, comprising sub-cohorts of aneurysmal subarachnoid hemorrhage, ischemic stroke, and traumatic brain injury. Furthermore, we had four healthy controls. Samples were systematically collected from patients treated at the University Hospital of Turku between 2017 and 2019, at early (1.50 ± 0.70 days) and late (9.17 ± 3.40 days) post-admission time points. Urinary p75NTR levels, measured by ELISA and normalized to creatinine, were compared against patients' outcomes using the modified Rankin Scale (mRS). Early urine samples showed no significant p75NTR concentration difference between favorable and unfavorable mRS groups. In contrast, late samples exhibited a statistically significant increase in p75NTR concentrations in the unfavorable group (p = 0.033), demonstrating good prognostic accuracy (AUC = 70.9%, 95% CI = 53-89%, p = 0.03). Assessment of p75NTR concentration changes over time revealed no significant variation in the favorable group (p = 0.992) but a significant increase in the unfavorable group (p = 0.009). Moreover, p75NTR concentration was significantly higher in ABI patients (mean ± SD 40.49 ± 28.83-65.85 ± 35.04 ng/mg) compared to healthy controls (mean ± SD 0.54 ± 0.44 ng/mg), irrespective of sampling time or outcome (p < 0.0001). In conclusion, late urinary p75NTR concentrations emerged as a potential prognostic biomarker for ABIs, showing increased levels associated with unfavorable outcomes regardless of the specific type of brain injury. While early samples exhibited no significant differences, the observed late increases emphasize the time-dependent nature of this potential biomarker. Further validation in larger patient cohorts is crucial, highlighting the need for additional research to establish p75NTR as a reliable prognostic biomarker across various ABIs. Additionally, its potential role as a diagnostic biomarker warrants exploration.

Abstract WP222: Temporally Differentially Expressed MikroRNAs In Serum Predict Recovery In Different Acute Brain Injuries

Background: Brain plasticity is important processes in recovering after different types of acute brain injuries such as aneurysmal subarachnoid hemorrhage (aSAH), ischemic stroke (IS) and traumatic brain injury (TBI). Knowledge gaps still exist which miRNAs contribute to recovery of the acute brain injuries.

Hypotheses: Temporally differentially expressed (DE) miRNAs after acute brain injuries may have association to outcome irrespective the type of the acute brain injury. MiRNAs that are DE across different type of brain injuries may reveal important conserved associations that can reflect important biological mechanisms and serve as a biomarker.

Methods: Prospective cohort (n=24) consisted of IS (n=8), aSAH (n=8) and TBI (n=8) patients. Two serum samples were collected per patient (early 24-48h and late 120-192h after injury). Outcome was measured 90 days after injury (mRS favorable 0-3 (n=15), unfavorable 4-6 (n=9). MiRNAs were extracted from the samples (total n = 48 samples). Sequencing was performed and DESeq2 was used to identify DE miRNAs. The miRNA putative target genes were predicted with miRWalk. Normalized expression values of identified DE miRNAs were used and linear canonical discriminant analysis (LDA) was performed. Canonical scores were used to build combinatory biomarker with logistic modelling predicting outcome.

Results: We identified 22 temporally DE miRNAs (p<0.05) that were in common across all acute brain injury types when compared between favorable and unfavorable groups. From this pool miRWalk target analysis identified 4 miRNAs (hsa-miR-146b-3p, hsa-miR-485-3p, hsa-miR-5010-5p, hsa-miR-485-5p) that targeted to known plasticity mechanism. LDA of these four miRNAs resulted an equation with canonical scores: 0.636 x [hsa-miR-146b-3p] + 0.576 x [hsa-miR-485-3p] + 0.652 x [hsa-miR-5010-5p] + 0.372 x [hsa-miR-485-5p]. The receiver operating characteristic curve generated showed AUC = 94.1%, 95% CI = (0.849, 1.00), p = 0.016

Conclusions: Results show that combinatory biomarker of identified miRNAs perform well across different type of brain injuries. Validation in larger cohort is justified. Identified common miRNAs also provide new targets for mechanistical validation in disease models of TBI and stroke.

Abstract TP234: Different Type Of Acute Brain Injuries Share Similar Pattern Of Lipidomic Profile Changes In Human Serum

Background: Neuronal recovering processes after acute brain injuries such as aneurysmal subarachnoid hemorrhage (aSAH), ischemic stroke (IS) and traumatic brain injury (TBI) are complex including brain plasticity and synaptic regeneration mechanisms. Temporal changes in lipidomic profile after different acute brain injuries may reveal new insights about brain plasticity, recovery and biomarker development after acute injury.

Hypotheses: Measurable temporal changes in serum lipidomic profile may be similar irrespective of the type of the brain injury and may reveal conserved molecular aberrations after different types of acute brain injuries. These common changes may also be associated to outcome and serve as possible biomarkers.

Methods: Prospective cohort (n=74) consisted of IS (n=30), aSAH (n=31) and TBI (n=13) patients. Serum samples were collected in two time points after the insult (early 24-48h and late 120-192h). Lipidomic profiling of 1153 lipids was performed using Lipidyzer Platform. The lipidomics data was analyzed with Metaboanalyst for ANOVA, PCA, heatmap, box plots with following settings: missing values were imputated with KNN using 20% cutoff, log-transformed and auto-scaled.

Results: We identified four diacylglycerols (DAG), one cholesterol ester (CE), seven triacylglycerols (TAG) and one sphingomyelin (SM) which showed increased levels in late serum samples across all types of brain injuries (p<0.05, FDR corrected). Four free fatty acids (FFA) and two phosphatidylethanolamines (PE) levels were decreased in late serum samples across all injury types (p<0.05, FDR corrected).

Conclusion: Changes in lipidomic profiles across time were identified. This suggests common lipidomic characteristics irrespective of the type of brain insult and encourage further studies. Interestingly, lipidomic profiles may be associated to recovery after acute brain injury and further analyses of this data will follow.

Abstract TP236: Temporal Metabolomic Profiling Exposed Affiliated Metabolites Altered And Associations To Outcome After Different Acute Brain Injuries

Background: Neuronal recovering processes after acute brain injuries such as aneurysmal subarachnoid hemorrhage (aSAH), ischemic stroke (IS) and traumatic brain injury (TBI) are complex including brain plasticity and synaptic regeneration mechanisms.

Hypotheses: Transient changes in metabolome after different acute brain injuries may reveal affiliated metabolites, metabolic pathways and associations that can also reflect important biological mechanisms. Measurable temporal changes in serum metabolomic profile may be similar irrespective of the type of the brain injury. These metabolomic commonalities may be associated to outcome.

Methods: Prospective cohort (n=74) consisted of IS (n=30), aSAH (n=31) and TBI (n=13) patients. Serum samples were collected in two time points after the insult (early 24-48h and late 120-192h). Orbitrap Profiling of 462 metabolites was used to measure metabolites. Outcome was measured 90 days after injury (mRS favorable 0-3, unfavorable 4-6). The metabolomics data was imputed for missing value using KNN with 20% cut off for missing value, log-transformed and autoscaled. For statistics, t-test and ANOVA was performed and FDR-corrected p-value 0.05 was considered to be statistically significant.

Results: We identified four similarly temporally increased metabolite levels across all acute brain injury types (p<0.05, FDR corrected). Twenty-eight metabolites were shown to have similar trend when only IS and TBI groups were compared. Whereas outcome analysis showed three metabolites associating both favorable and unfavorable outcome across all acute brain injury types (p<0,05, FDR corrected). IS and TBI groups combined twenty common metabolites were identified to associate favorable and twenty-three with unfavorable outcome (p<0,05, FDR corrected).

Conclusion: Similar metabolic changes across time were identified with apparent associations to outcome. This suggests important common metabolic characteristics irrespective of the type of brain insult and encourage further studies and validation. Identified metabolites may be further developed as a prognostic biomarker and may indicate new metabolic pathways active irrespective the type of brain injury reflecting biological mechanisms.

Genetic analysis reveals novel variants for vascular cognitive impairment

OBJECTIVES

The genetic background of vascular cognitive impairment (VCI) is poorly understood compared to other dementia disorders. The aim of the study was to investigate the genetic background of VCI in a well-characterized Finnish cohort.

MATERIALS & METHODS

Whole-exome sequencing (WES) was applied in 45 Finnish VCI patients. Copy-number variant (CNV) analysis using a SNP array was performed in 80 VCI patients. This study also examined the prevalence of variants at the miR-29 binding site of COL4A1 in 73 Finnish VCI patients.

RESULTS

In 40% (18/45) of the cases, WES detected possibly causative variants in genes associated with cerebral small vessel disease (CSVD) or other neurological or stroke-related disorders. These variants included HTRA1:c.847G>A p.(Gly283Arg), TREX1:c.1079A>G, p.(Tyr360Cys), COLGALT1:c.1411C>T, p.(Arg471Trp), PRNP: c.713C>T, p.(Pro238Leu), and MTHFR:c.1061G>C, p.(Gly354Ala). Additionally, screening of variants in the 3'UTR of COL4A1 gene in a sub-cohort of 73 VCI patients identified a novel variant c.*36T>A. CNV analysis showed that pathogenic CNVs are uncommon in VCI.

CONCLUSIONS

These data support pathogenic roles of variants in HTRA1, TREX1 and in the 3'UTR of COL4A1 in CSVD and VCI, and suggest that vascular pathogenic mechanisms are linked to neurodegeneration, expanding the understanding of the genetic background of VCI.

Abstract P809: A Comprehensive P75 Neurotrophin Receptor Gene Network and Pathway Analyses Identifying New Target Genes for Stroke Recovery

Introduction: Therapeutic interest into the neurotrophins resides in their ability to regulate the process of neuronal and synaptic regeneration following acute brain injuries such as intracerebral hemorrhage, subarachnoid hemorrhage and ischemic stroke. P75 neurotrophic receptor (p75NTR) is an important receptor for the role of neurotrophins in modulating brain plasticity and apoptosis. The current understanding of the role of p75NTR in cellular adaptation following pathological insults remains blurred.

Methods: We identified p75NTR and related genes through extensive data mining of a PubMed literature search including published works related to p75NTR from the past 20 years. Bioinformatic network and pathway analyses of identified genes (n=235) were performed using ReactomeFIViz in Cytoscape based on the highly reliable Reactome functional interaction network algorithm. This approach merges interactions extracted from human curated pathways with predicted interactions from machine learning.

Results: Genome-wide pathway analysis showed total of 16 enriched hierarchical clusters. A total of 278 enriched single pathways were also identified (p<0.05, FDR corrected). Gene network analyses showed multiple known and new targets in the p75NTR gene network. This study provides a comprehensive analysis and investigation into the current knowledge of p75NTR signaling networks and pathways.

Discussion: This study provides the largest comprehensive gene and functional network library of p75NTR and incorporates current knowledge using a large dataset approach that increases the overall understanding of complex p75NTR networks. These results suggest both new possible target genes for further investigation in p75NTR research, while also validating previously conducted research. These results can be used to generate novel hypotheses to gain a greater understanding of p75NTR in stroke.

Future directions: We are currently sequencing miRNA libraries from ischemic and hemorrhagic stroke patients’ plasma with longitudinal plasma samples and clinical data. This data together with presented results will be used to test identified novel targets in p75NTR engineered models in order seek novel therapeutic strategies to increase recovery after stroke.

A comprehensive p75 neurotrophin receptor gene network and pathway analyses identifying new target genes

P75 neurotrophic receptor (p75NTR) is an important receptor for the role of neurotrophins in modulating brain plasticity and apoptosis. The current understanding of the role of p75NTR in cellular adaptation following pathological insults remains blurred, which makes p75NTR’s related signaling networks an interesting and challenging initial point of investigation. We identified p75NTR and related genes through extensive data mining of a PubMed literature search including published works related to p75NTR from the past 20 years. Bioinformatic network and pathway analyses of identified genes (n = 235) were performed using ReactomeFIViz in Cytoscape based on the highly reliable Reactome functional interaction network algorithm. This approach merges interactions extracted from human curated pathways with predicted interactions from machine learning. Genome-wide pathway analysis showed total of 16 enriched hierarchical clusters. A total of 278 enriched single pathways were also identified (p < 0.05, false discovery rate corrected). Gene network analyses showed multiple known and new targets in the p75NTR gene network. This study provides a comprehensive analysis and investigation into the current knowledge of p75NTR signaling networks and pathways. These results also identify several genes and their respective protein products as involved in the p75NTR network, which have not previously been clearly studied in this pathway. These results can be used to generate novel hypotheses to gain a greater understanding of p75NTR in acute brain injuries, neurodegenerative diseases and general response to cellular damage.

Effectiveness of primary and comprehensive stroke centers: PERFECT stroke: a nationwide observational study from Finland

BACKGROUND AND PURPOSE

Previous studies show better outcomes for patients with stroke receiving care in stroke units, but many different stroke unit criteria have been published. In this study, we explored whether stroke centers fulfilling standardized Brain Attack Coalition criteria produce better patient outcomes than hospitals without stroke centers.

METHODS

We did an observational register-linkage study of all patients with ischemic stroke treated in Finland between 1999 and 2006. After exclusion of recurrent strokes and nonanalyzable patients, we included 61 685 consecutive patients treated in 333 hospitals classified in national audits either as Comprehensive Stroke Centers, Primary Stroke Centers, or General Hospitals according to Brain Attack Coalition criteria. Primary outcome measures were case-fatality and being in institutional care 1 year after stroke.

RESULTS

Care in stroke centers was associated with lower 1-year case-fatality and reduced institutional care compared with General Hospitals. The number-needed-to-treat to prevent 1 death or institutional care at 1 year was 29 for Comprehensive Stroke Centers and 40 for Primary Stroke Centers versus General Hospitals. Patients treated in stroke centers had lower mortality during the entire follow-up of up to 9 years and their median survival was increased by 1 year.

CONCLUSIONS

This study shows a clear association between the level of acute stroke care and patient outcome and supports use of published criteria for primary and comprehensive stroke centers.

CADASIL: the most common hereditary subcortical vascular dementia

Cerebral autosomal dominant arteriopathy with subcortical infarct and leukoencephalopathy (CADASIL) is the most common hereditary subcortical vascular dementia. It is caused by the defective NOTCH3 gene, which encodes a transmembrane receptor; over 170 different mutations are known. The main clinical features are migraine with aura (often atypical or isolated), strokes, cognitive decline/dementia and psychiatric symptoms. Executive and organizing cognitive functions are impaired first, memory is affected late. Typical MRI findings are T2 weighted hyperintensities in temporopolar white matter and the capsula externa. Smooth muscle cells in small arteries throughout the body degenerate and vessel walls become fibrotic. In the brain, this results in circulatory disturbances and lacunar infarcts, mainly in cerebral white matter and deep gray matter. The exact pathogenesis is still open: a dominant-negative toxic effect is suggested, possibly related to Notch3 misfolding. Diagnosis is reached either by identifying a pathogenic NOTCH3 mutation or by electron microscopic demonstration of granular osmiophilic material in a (skin) biopsy. Only symptomatic treatment is available at present.

Arterioles of the Lenticular Nucleus in CADASIL

BACKGROUND AND PURPOSE

In cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) the arteriopathy leads to recurrent infarcts in cerebral white matter (WM) and deep gray matter (GM), whereas cortex is spared. To assess the pathogenesis of deep GM infarcts, we analyzed structural changes in arterioles of the lenticular nucleus (LN) in 6 CADASIL patients.

METHODS

Five elderly and one 32-year-old deceased CADASIL patients were studied. Seven elderly and 4 young deceased persons without cerebrovascular diseases served as controls. In addition to immunohistochemical analysis the external and luminal diameters of arterioles in the LN, cerebral cortex and WM were measured. The thickness of arteriolar wall and sclerotic index were calculated.

RESULTS

In CADASIL patients, LN arterioles were immunoreactive for the extracellular domain of Notch3 and collagen I, whereas alpha-smooth muscle actin staining was irregular or negative. No major leakage of plasma fibrinogen or fibronectin was observed. Although in patients the walls of LN arterioles were significantly thicker than in controls, definite stenosis was not observed. Arteriolar lumina in the LN were not only significantly larger than in the WM, where most lacunar infarcts in CADASIL occur, but also larger than in cortical GM, where infarcts virtually never exist.

CONCLUSIONS

Fibrotic thickening of the arteriolar walls without consequent stenosis occurs in the LN of CADASIL patients. The pathogenesis of lacunar infarcts in the WM and LN seem to be different, stenosis in the former and probably hemodynamic disturbances in the latter.

Ophthalmologic findings in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: a cross-sectional study

OBJECTIVE

To determine the ophthalmologic findings, especially the nature of retinal vascular changes, and their clinical significance in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a disease that causes migraine, recurrent strokes, and finally subcortical vascular dementia.

DESIGN

Cross-sectional study.

PARTICIPANTS

Thirty-eight CADASIL patients (19 to 61 years old; 20 in a prestroke group, 15 in a stroke group, and 3 in a dementia group), all with the R133C NOTCH3 mutation and including one homozygous patient, underwent a detailed ophthalmologic examination.

METHODS

Common cardiovascular risk factors were evaluated. Ophthalmologic examination included best-corrected visual acuity, anterior- and posterior-segment biomicroscopy, and measurement of intraocular pressure. In 33 patients and 16 healthy controls (20-64 years old), retinal fundus photographs were taken. Diameters of all arterioles and venules located in the area from 0.5 to 1.0 disc diameters from the optic disc margin were measured with a computer-based program and arteriole-to-venule (A/V) ratios were calculated from digitized photographs.

RESULTS

General arterial narrowing and arteriovenous nickings were common. Straightening of the retinal arterioles and a marked wall reflex (n = 6) occurred. The A/V ratio of CADASIL patients was significantly (P< 0.001) lower than that of controls. One patient had one retinal microinfarct and hemorrhages. The homozygous patient had a chorioretinal scar as a sign of circulatory deficiency. Anterior-segment changes included mild iris atrophy (n = 5) and various degrees of lens opacities. Visual acuity was normal in all but 2 patients, who had cataract and amblyopia.

CONCLUSIONS

The generalized arteriopathy of CADASIL causes a wide variety of changes in retinal arterioles but only minimal functional disturbances. These findings are consistent with alterations in arterioles in the cerebral cortex with which the retina and its arterioles are analogous, but contrast with the severe damage of cerebral white matter arterioles.

Neurologic symptoms are common during gestation and puerperium in CADASIL

Based on a structured questionnaire and medical records, the authors found that 12 of 25 mothers with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with the R133C NOTCH3 mutation had had neurologic symptoms in 17 of their 43 pregnancies, most commonly hemiparesthesia (76%), hemiparesis (36%), aphasia (65%), and visual disorders (47%). In 82% of the patients, the symptoms were the first manifestation of CADASIL. The symptoms were most common during puerperium and in patients older than age 30.

The persistence of psychiatric deviance from the age of 8 to the age of 15 years

BACKGROUND

Earlier research has shown that psychiatric problems in children tend to persist over years. This investigation assessed the persistence of psychiatric deviance among children over a 7-year period from the age of 8 to the age of 15 years. We also explored the relationship between problems leading to special attention at the well-baby clinics before school age and future psychiatric deviance.

METHODS

The study material consisted of three questionnaires filled out by the parents, teachers and children themselves (N = 1268) at three time points, together with data concerning the children gathered from the records of well-baby clinics.

RESULTS

At the age of 15 years, girls scored higher than boys on the parental scale and on the Beck's Depression Inventory (BDI), while boys scored higher than girls on the teachers' scale. Parental ratings had a high correlation over 3 years and a moderate correlation over 7 years. Teachers' and children's ratings correlated moderately over 3 years, but did not correlate significantly over 7 years. The probability of being deviant at the age of 15 years was elevated if the child scored high on the parents' or teachers' scale at the age of 8 or 12 years, or on the Children's Depression Inventory (CDI) at the age of 12 years. Problems noted by health professionals (problems in growth, somatic diseases, emotional/behavioural problems of the child, psychosocial problems of the family) before school age were related to future deviance on the parental scale. Emotional/behavioural problems before school age elevated the probability of scoring high on the teachers' scale at the age of 15, and problems in psychomotor development elevated the probability of scoring high on the BDI.

CONCLUSIONS

Psychiatric deviance is persistent over several years in children. Primary health care professionals can identify children who are at risk for future psychiatric problems.